From Halopedia, the Halo wiki
Maps played in Team Doubles
Note: All maps have equal chance of being selected.
Gametypes Played in Team Doubles
A limited hopper, based on Team Doubles, was introduced on Thursday, February 14th at 10a.m. PST by Bungie, titled "St. Valentine's Day Massacre" . This ran until Monday 18th February, during which Bungie monitored certain actions performed by players, and gave out Recon Armor to the winners.
As with normal Team Slayer, multiple tactics can be employed.